Several techniques exist to find, analyze, or predict subterranean reservoirs of hydrocarbons, natural gas, water, and/or other substances. For example, capillary pressure analysis can be performed on an actual rock sample from a reservoir well core sample. The capillary pressure analysis can provide concrete information about the porosity and permeability of types of rock present in the rock sample and to provide useful information about rock characteristics within a reservoir formation. Actual rock sample analysis is normally very expensive and time consuming. Another less expensive and faster method is to use saturation modeling approaches with rock type and assigned permeability characteristics. Current saturation modeling approaches assume that the petrophysical properties of rocks can be defined entirely from lithologic log data. Based on the rock type or assigned permeability characteristics, water saturation of the rock can be predicted. Measured water saturation from log data is used purely for comparison purposes.